You may know that those colorful Victorian houses visible from the Arroyo Seco Parkway (the old Pasadena Freeway) are all part of the Heritage Square Museum. You may have visited the 1908 Arts and Crafts Gamble House once or checked out an exhibit at the Southwest Museum — 100 years old this year.

How about the 19th century Lummis Home? The Pasadena Museum of History and Finnish Folk Museum — the latter a rarity in the United States? Or the Los Angeles Police Museum, with memorabilia going back to the 1800s, just over the border in Highland Park?

All of these singular attractions are up for sampling on Museums of the Arroyo Day (MOTA), returning for a 25th year on May 18 from noon to 5 p.m. During this celebration of the history, art, architecture and culture of the Arroyo Seco corridor, each museum is offering free admission, special activities and exhibitions for all ages.

The Heritage Square Museum buildings, spanning the years 1850 to 1950, "will be open for touring," said Jessica Rivas, director of education and volunteer programs. "It's fun," she said, "when people get off the freeway and stop and are amazed that these houses are here." Activities will include Victorian Era dance lessons, "arts and crafts for kids at a couple of different skill levels, period games and storytellers," and in addition to a blacksmithing demonstration, Rivas said, "some woodcarvers will be here doing lathe work and we'll have a Spanish American war encampment set up."

Each of the participating museums will also feature a rare "From the Vault" exhibit, special to MOTA Day, Rivas noted. At Heritage Square, that will be a never-before-displayed set of handmade children's furniture, crafted in 1910.

The Pasadena Museum of History, a museum, research library and archive which encompasses the recently remodeled 1906 Beaux Arts Fenyes Mansion, is also home to the Finnish Folk Museum. "It's full of wonderful Finnish artifacts from the 1800s, set up like a Finnish farmhouse would have been at that time," said Brad Macneil, the Museum's education programmer. "Crown City Jubilee" exhibit celebrates notable anniversaries of other Pasadena institutions, organizations and businesses, some well over 100 years old. (The 50-year-old iconic Pasadena eatery, Pie 'n Burger, will be represented by a food truck on the premises.) Live music will be provided by California based acoustic group, the 3/3rds. "It's a great family day," Macneil said.

The Pasadena Museum's "From the Vault" item on display: the Bandini Chair, crafted out of steer horns and said to have belonged to the family whose 19th century patriarch was prominent Southern California landowner Don Juan Bandini. ("We're still exploring it to see if that's true," Macneil said.)

Among other free MOTA offerings: Tours of the Charles and Henry Greene Gamble House, a National Historic Landmark, and the turn-of-the-century Lummis Home, built with stones from the arroyo. Visitors to the Autry's Southwest Museum (Mt. Washington campus) can see the current exhibitions, "Four Centuries of Pueblo Pottery" and "Highlights From the Southwest Museum Collection", and explore a special display of archival recordings from museum founder Charles Lummis' wax cylinder collection preserving songs of the Californios and Native Americans.

The Los Angeles Police Museum offers a look at LAPD history with memorabilia going back to 1869 and exhibits related to the Patty Hearst kidnapping and other famous cases on permanent display. Visitors can tour the facility, pose for police booking photos, experience a restored paddy wagon, circa 1955, and see what it feels like to sit inside a "retired" police helicopter.

"All of these museums are tied into the history of the Arroyo," said Macneil. "They've all had their struggles, but they're still here, with interesting buildings and collections. The other thing that makes this event unique is that it's a collaboration with museums in two different communities: Los Angeles and Pasadena. What unites us is that we're all along the Arroyo."

"It's a great day to come out and explore the history of the area and see what this part of the city has to offer," said Rivas. "But," she cautioned, "I think a lot of people say, 'we'll find a way to cram six museums into five hours,' but most people make it to two. So I always recommend start with the one you want to go to the most, and don't anticipate making it to them all, because there's just too much to see."